I don't really agree to they are a rip. Those tilesets in the gameboy game are far more limited and have far less details. Just because they have the same theme and certain tiles look the same does not mean they are ripped off each other. You may find that Nick probably never played the game (considering it was released in his adult age, and I really doubt he'd be playing Lion King on a GBA).

Please consider that some of the concepts nick stole/ripped were old ones, probably ones that he liked as a child himself.